Generally, an electric toothbrush is a tool that uses a vibration motor to vibrate a bristle holder holding the bristles to clean teeth. Usually, an electric toothbrush has a grip and a head portion, wherein a vibration motor and a battery are received in the grip, and the bristle holder is provided at the head portion.
The vibration motor installed at the grip is operated by the power of the battery to generate vibrations. The vibrations then transfer to the head portion to vibrate the bristle holder. In other words, the vibrations are not directly generated at the head portion but generated at the grip and then transferred to the head portion. During this vibration transferring procedure, the vibrations partially disappear or are transferred to the hand. Accordingly, since the vibration motor must generate that much more vibrations, it is considered to be ineffective.
To generate that much more vibrations, a larger vibration motor should be installed, more power should be supplied, and the size of the toothbrush should be increased, which all contribute to the ineffectiveness.